Subtle increase in leukocyte counts in association with drinking and smoking habits.

Peripheral leukocyte counts were examined in venous blood of more than 800 male workers exposed to toluene, xylenes, a combination of the two, or neither. Information on the social habits of smoking and drinking was obtained in an occupational health interview. The analysis showed that smoking (15 cigarettes/day on average) induced a significant increase (by 7%) in leukocyte counts, and that an additional increase was induced when the drinking habit was coupled with smoking. Drinking alone tended to increase the leukocyte counts but the effect was statistically nonsignificant, possibly because the number of nondrinking smokers was limited. The study stresses the importance of paying attention to smoking and drinking habits when evaluating hematological parameters such as peripheral leukocyte counts in solvent-exposed workers.